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1.0 PROCESS DESCRIPTION <br /> The system tested was comprised of a 1000 gallon single-compartment septic tank(equipped with an eight- <br /> inch diameter BiotubeTm effluent filter -1/8 inch screen), a distribution box, and three rows of six Eljen <br /> GSF/A42 Geotextile Sand Filter modules(each module 48 inches x 24 inches) placed over eighteen inches <br /> of ASTM C33 sand and 12 inches of a 50/50 ASTM C33, hard woodchip mixture. A daily loading rate of 450 <br /> gallons is provided into the septic tank. The resulting hydraulic loading rate using the basal area of the units <br /> alone for calculation (2 ft. x 24 ft. = 48 ft.) approximates 3.125 gal/day/sq. ft. <br /> 2.0 PERFORMANCE EVALUATION <br /> 2.1 Description of Plant Evaluated <br /> The Eljen GSF Denitrification DN450 System is a drainfield adsorption wastewater treatment system. The <br /> GSF operates by growing and maintaining a biomat within the Eljen GSF A42 units. It is comprised of a two- <br /> stage Bio-MattTM pre-treatment process. The geotextile modules apply aerobic effluent to the <br /> sand/lignocellulose layer for denitrification. The mixture of lignocellulose and sand allows for an anaerobic <br /> environment with a carbon food source. This promotes denitrification. <br /> A perforated pipe is centered above the GSF module to distribute septic effluent over and into corrugations <br /> created by the cuspated core of the geotextile module. The septic effluent is filtered through the Bio-Matt <br /> fabric. The module's design provides increased surface area for biological treatment that exceeds the <br /> module's footprint. Open air channels within the module support aerobic bacterial growth on the modules <br /> geotextile fabric interface. A geotextile fabric covers the top and sides of the GSF module to protect the <br /> Specified Sand and soil from clogging, while maintaining effluent storage within the module. <br /> The sand supports nitrification of the effluent. Effluent drips into the Specified Sand layer and supports <br /> unsaturated flow into the sand and lignocellulose layer. <br /> The lignocellulose layer and sand creates a low oxygen environment which allows the treated effluent to <br /> bond with the carbon source, promoting denitrification. Effluent passes through and then is ready for final <br /> disposal. <br /> 15/10/055/0030 This report may not be reproduced in whole or in part Page 7 of 59 <br /> Final Report without the expressed written consent of NSF International January 2019 <br />